U.S. patent application number 11/628566 was filed with the patent office on 2007-11-15 for advanced multi-resonant, multi-mode gamma beam detection and imaging system for explosives, special nuclear material (snm), high-z materials, and other contraband.
Invention is credited to Joseph H. JR. Brondo.
Application Number | 20070263767 11/628566 |
Document ID | / |
Family ID | 35503765 |
Filed Date | 2007-11-15 |
United States Patent
Application |
20070263767 |
Kind Code |
A1 |
Brondo; Joseph H. JR. |
November 15, 2007 |
Advanced Multi-Resonant, Multi-Mode Gamma Beam Detection And
Imaging System For Explosives, Special Nuclear Material (Snm),
High-Z Materials, And Other Contraband
Abstract
A method and apparatus combining Gamma Resonance Absorption,
Gamma Resonance Fluorescence, Gamma Induced Photofission, Dual Beam
Gamma Energy Absorptiometry modality in a single system for
contraband detection/identification. Such contraband detection
systems utilize novel proton beam target devices capable of
generating single or multiple monoenergetic gamma ray beams used in
detection/measurement of contraband, for simultaneous detection of
multiple target objects in a single scan.
Inventors: |
Brondo; Joseph H. JR.;
(Wainscott, NY) |
Correspondence
Address: |
SCULLY, SCOTT, MURPHY & PRESSER, P.C.
400 GARDEN CITY PLAZA
SUITE 300
GARDEN CITY
NY
11530
US
|
Family ID: |
35503765 |
Appl. No.: |
11/628566 |
Filed: |
August 6, 2004 |
PCT Filed: |
August 6, 2004 |
PCT NO: |
PCT/US04/25446 |
371 Date: |
February 21, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60576496 |
Jun 3, 2004 |
|
|
|
Current U.S.
Class: |
378/57 |
Current CPC
Class: |
G01V 5/0069 20161101;
G01V 5/0033 20130101 |
Class at
Publication: |
378/057 |
International
Class: |
G01N 23/04 20060101
G01N023/04 |
Claims
1. A multi-modal contraband detection system for detecting
contraband materials in one or more target objects, said system
comprising: a proton beam accelerator device for producing a high
energy beam of protons at a specific energy; a single proton beam
target for generating one or more gamma ray beams in response to
impinging high energy beam of protons, said generated one or more
gamma ray beams being simultaneously directed to a target object;
and, a plurality of detector means associated with the target
object, wherein said plurality of detector means provide multiple
modes of detecting presence of contraband materials in each said
target object.
2. The multi-modal contraband detection system of claim 1, wherein
said plurality of detector means includes one or more selected from
the group comprising: a means for detecting gamma rays; a means for
detecting neutrons; a nuclear resonance fluorescence detector array
to detect fluorescing reaction on an incoming proton beam side of a
target object; a gamma-insensitive neutron detector array to detect
neutrons emitted in a photofission reaction with material included
in a target object; a high-Z sandwich detector; a non-resonant
detector array; a resonant detector array enriched with a sample of
an element that is being detected; means selected from the group
comprising: X-ray/CT-X-ray detection, Dual energy X-ray detection,
multiple energy/multiple beam CT-X-ray and X-ray Diffraction; a
Terahertz interrogation device for detection; a Nuclear Quadrapole
Resonance detector adapted to provide detection of specific
molecules; an NMR/ESR device adapted to provide detection of
specific free radicals; and a passive detector means, or
combinations thereof.
3-15. (canceled)
16. The multi-modal contraband detection system of claim 1, further
comprising means for rotating a proton beam target to generate
multiple gamma ray beams in response to impinging proton beams.
17. The multi-modal contraband detection system of claim 1, wherein
said proton beam target generates one or more gamma ray beams at
one or more angles, said system further comprising means for
orienting an angle of said proton beam target relative to a
direction of said impinging proton beam to control directivity of
said gamma ray beams.
18. The multi-modal contraband detection system of claim 16,
wherein directivity of said gamma ray beams is controlled to become
parallel with a direction of said impinging target proton beam.
19. The multi-modal contraband detection system of claim 1, wherein
said proton beam target generates one or more gamma ray beams at
one or more angles, one or more of said plurality of detector means
being oriented at an angle relative to said proton beam target for
receiving said gamma ray beams.
20. The multi-modal contraband detection system of claim 5, further
comprising a means for producing a gamma ray beam pulse for
enabling detection of delayed neutrons emitted in a photofission
reaction with material included in a target object.
21. The multi-modal contraband detection system of claim 19,
wherein said means for producing a gamma ray beam pulse includes a
shutter device timed to interrupt a generated gamma ray beam to
provide said gamma ray beam pulse.
22. The multi-modal contraband detection system of claim 1, wherein
one of said plurality of detector means includes an energy
discriminating detector and/or a position sensitive detector.
23. (canceled)
24. The multi-modal contraband detection system of claim 1, wherein
one said proton beam target is of a composite configuration
comprising two or more different materials for generating multiple
gamma ray beams each associated with a reaction of protons with a
respective material.
25. The multi-modal contraband detection system of claim 1, wherein
one said proton beam target is of a layered configuration
comprising two or more different materials for generating multiple
gamma ray beams each associated with a reaction of protons with a
respective material.
26. The multi-modal contraband detection system of claim 1, wherein
one said proton beam target is of a segmented configuration
comprising at least two different materials for generating multiple
gamma ray beams each associated with a reaction of protons with a
respective material.
27. The multi-modal contraband detection system of claim 1, further
comprising: a plurality of proton beam targets, each adapted for
generating one or more gamma ray beams in response to impinging
high energy beam of protons; and, one or more switching means for
directing said high energy beam of protons to each of plurality of
said proton beam targets along different paths, wherein each said
plurality of proton beam targets generates one or more gamma rays
in response to impinging beam of protons, and each of said
generated one or more gamma ray beams being directed to multiple
target objects to enable detection of contraband material in
multiple target objects.
28. The multi-modal contraband detection system of claim 27,
further including means for timing switching of said switching
means to enable raster scan of each of said generated one or more
gamma ray beams for detecting contraband in multiple target
objects.
29. The multi-modal contraband detection system of claim 27,
wherein said switching means is timed to enable simultaneous
detection of contraband in multiple target objects.
30. The multi-modal contraband detection system of claim 1, further
comprising: a plurality of proton beam targets, each adapted for
generating one or more gamma ray beams in response to impinging
high energy beam of protons; and, a proton beam splitter device
associated with said accelerator device for producing a plurality
of high energy proton beams for impingement upon a respective one
of said plurality of proton beam targets, wherein each of said
plurality of proton beam targets generates one or more gamma rays
in response to impinging beam of protons, and each of said
generated one or more gamma ray beams being directed to multiple
target objects to enable simultaneous detection of contraband
material in multiple target objects.
31. The multi-modal contraband detection system of claim 7, wherein
a non-resonant detector array includes a detector selected from:
BGO, sodium iodide detector, or other gamma detectors or neutron
detectors.
32. The multi-modal contraband detection system of claim 1, wherein
said system enables detection of contraband materials by detecting
both nuclear resonance fluorescence and/or nuclear resonance
absorption in a single scan.
33. The multi-modal contraband detection system of claim 1, further
comprising: an additional proton beam accelerator device for
producing a second high energy beam of protons at a specific
energy; and, an additional proton beam target for generating one or
more gamma ray beams in response to said second impinging high
energy beam of protons, said generated one or more gamma ray beams
being simultaneously directed to a further target object, whereby
simultaneous detection of contraband in at least two target objects
is enabled.
34. The multi-modal contraband detection system of claim 1, wherein
one of said plurality of detector means is adapted to measure Z of
a contraband material contained in said target objects.
35. The multi-modal contraband detection system of claim 9, wherein
one of said plurality of detector means is adapted to measure
density of a contraband material contained in said target
objects.
36. The multi-modal contraband detection system of claim 9, wherein
one of said plurality of detector means includes means adapted to
generate one or more images selected from the group comprising:
planar, 2D, or CT, and 3D images.
37. The multi-modal contraband detection system of claim 1, adapted
to perform stand-off detection.
38. The multi-modal contraband detection system of claim 1, adapted
to be mounted on vehicle for providing a single-sided scan.
39. A vehicle comprising a contraband detection system for
providing stand-off detection of contraband materials in a target
object, said contraband detection system comprising: a proton beam
accelerator device for producing a high energy beam of protons at a
specific energy; a single proton beam target for generating one or
more gamma ray beams in response to impinging high energy beam of
protons, said generated one or more gamma ray beams being
simultaneously directed to a target object; and, a plurality of
detector means associated with the target object, wherein said
plurality of detector means provide multiple modes of detecting
presence of contraband materials in each said target object.
40. (canceled)
41. A multi-modal contraband detection system adapted to detect
contraband material in containers traveling on a conveyor, said
multi-modal contraband detection system comprising: a proton beam
accelerator device for producing a high energy beam of protons at a
specific energy; a single proton beam target for generating one or
more gamma ray beams in response to impinging high energy beam of
protons, said generated one or more gamma ray beams being
simultaneously directed to a container; and, a plurality of
detector means providing multiple modes of detecting presence of
contraband materials in said container.
42-44. (canceled)
45. A multi-modal contraband detection system for detecting
contraband materials in one or more target objects, said system
comprising: a plurality of proton beam accelerator devices each for
producing a high energy beam of protons at specific energies; a
plurality of proton beam targets each for generating one or more
gamma ray beams in response to an impinging high energy beam of
protons from a respective accelerator, said generated one or more
gamma ray beams being simultaneously directed to one or more target
objects; and, a plurality of detector means associated with the one
or more target objects, wherein said plurality of detector means
provide multiple modes of detecting presence of contraband
materials in each said target object.
46. (canceled)
47. A method of detecting contraband materials in one or more
target objects, said method comprising: a) providing a proton beam
accelerator device for producing a high energy beam of protons at a
specific energy; b) providing a single proton beam target for
generating one or more gamma ray beams in response to impinging
high energy beam of protons, said generated one or more gamma ray
beams being simultaneously directed to a target object; and, c)
providing multiple modes of detecting presence of contraband
materials in each said target object by implementing a plurality of
detector means.
48-71. (canceled)
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to systems and methods for
contraband detection/identification that employ modalities
incorporating Gamma Resonance Absorption, Gamma Resonance
Fluorescence, Gamma Induced Photofission, and Dual Beam Gamma
Energy Absorptiometry techniques and combinations thereof in a
single system.
[0003] 2. Description of the Prior Art
[0004] Systems for detecting nitrogen based elements in contraband
materials are fairly well known. These systems basically utilize
the irradiation of such materials with gamma rays and the detection
of gamma rays emitted or absorbed by the materials after subjecting
them to the input gamma rays of specific energy to be
preferentially absorbed or to induce fluorescence in the specific
elemental material being detected. One technique of such detection
is Gamma Resonance Absorption (GRA) analysis. This type of system
generally utilizes the effect of gamma ray absorption by the
nucleus of the objects being interrogated during irradiation. The
concentration of these gamma rays are detected by gamma ray
detectors or arrays of detectors and the signals analyzed to
determine the concentrations of chemical elements which make up the
object being interrogated. These elements are found in explosives
or illicit drugs in differing quantities, ratios and
concentrations. By calculating and determining the ratios and
concentrations, it is possible to identify and differentiate
targeted contraband substances.
[0005] In such Contraband Detection Systems (CD or CDS), an example
of which is shown in FIG. 1(a), a proton beam 10 is generated that
is directed to a proton beam target device 12 that generates a
gamma ray fan 15 that is directed to a target object 20 such as a
rotating baggage container. Such a GRA CDS system is described in
U.S. Pat. No. 5,784,430 the whole contents and disclosure of which
is incorporated by reference as if fully set forth herein. Such CD
systems are distinguishable by the manner in which the proton beam
is generated: 1) Electrostatic Accelerator based, and 2) RF
Accelerator based. An early form of the Electrostatic Accelerator
based CDS comprises a high current (e.g., 10 mA) electrostatic
accelerator, a specially designed proton beam target 12 for gamma
generation, and a detector such as segmented and arrayed Bismuth
Germinate (BGO) detectors 25. The accelerator produces a beam of
protons 10, e.g., at energies of about 1.75 MeV, with a very narrow
energy spread. As shown in FIG. 1(b), this high energy proton beam
is bombarded onto the specially designed target 12 which is coated
with a thin film of .sup.13C (of about 1 micron thick) to generate
resonant gamma rays 15a at an energy of about 9.17 MeV by the
reaction .sup.13C(p,.gamma.).sup.14N and, additionally, generates
non-resonant gamma emissions 15b. The resultant gamma rays 15a are
preferentially absorbed by .sup.14N in explosives-type contraband.
The penetrating power of the gamma rays combined with a tomographic
detection scheme allows 3-D images of the total density and select
element density in the interrogated cargo/luggage/container to be
generated which is then utilized to detect for the presence of
concealed explosives utilizing the ratio of resonant to
non-resonant absorption thereby providing the ratio of Nitrogen
density to total density.
[0006] With the on-going threat of terrorism all over the world,
the need has come for improved means of detecting contraband
materials, including nitrogen and nuclear containing explosives
that may be concealed in vehicles such as cars, trucks automobiles,
shipping containers, airplanes, etc. This requires the
implementation of improved proton beam target devices. The need has
also come for a versatile, multi-mode, single CDS that employs a
variety of non-invasive active and passive detection techniques
that can be used for detecting a variety of target materials,
including nuclear materials.
[0007] It would thus be highly desirable to provide a Contraband
Detection System and methodology incorporating numerous means in
combination as a single stand alone system or, operated as separate
systems with single or multiple capabilities utilizing single or
multiple non-intrusive active gamma beam probes to detect, analyze
and/or image the contents of objects, e.g., shipping containers,
cargo, parcels, luggage, trucks, vehicles, railroad cars, mail,
checkpoints, border crossings etc.
[0008] It would be further highly desirable to provide a CDS and
methodology providing a non-intrusive, single scan means for
detecting explosives, nuclear bombs and nuclear materials,
shielding of nuclear or other materials, drugs, chemical warfare
agents and other contraband of interest. The detection can be
utilized in various configurations including inline, portal, remote
and standoff.
[0009] It would be additionally desirable to provide a CDS and
methodology for providing a non-intrusive, single pass/multiple
scan means for detecting explosives, nuclear bombs and nuclear
materials, shielding of nuclear or other materials, drugs, chemical
warfare agents and other contraband of interest. The detection can
be utilized in various configurations including inline, portal,
remote and standoff.
[0010] It would be highly desirable to provide a novel proton beam
target design of increased durability that is capable of better
withstanding impact of high energy proton beams utilized in the
generation of gamma rays for such CDS systems.
SUMMARY OF THE INVENTION
[0011] The present invention is directed to a method and apparatus
incorporating numerous means in combination as a single stand alone
system and/or operated as separate systems and/or operated as an
integrated system comprised of multiple systems with single or
multiple capabilities utilizing single or multiple non-intrusive
active gamma beam probes to detect, analyze and/or image the
contents of objects i.e. shipping containers, cargo, luggage,
trucks, vehicles, railroad cars, mail, checkpoints, border
crossings etc. The apparatus provides a single pass/multiple scan
means of detecting explosives, nuclear bombs and nuclear materials,
shielding of nuclear or other materials, drugs, chemical warfare
agents and other contraband of interest. The detection can be
utilized in various configurations including inline, portal, remote
and standoff.
[0012] Thus, according to the second aspect of the invention there
is provided a multi-modal contraband detection system for detecting
contraband materials in one or more target objects, the system
comprising: a proton beam accelerator device for producing a high
energy beam of protons at a specific energy; a single proton beam
target for generating one or more gamma ray beams in response to
impinging high energy beam of protons, the generated one or more
gamma ray beams being simultaneously directed to a target object;
and, a plurality of detector means associated with the target
object, wherein the plurality of detector means provide multiple
modes of detecting presence of contraband materials in each said
target object. One of the plurality of detector means includes a
nuclear resonance fluorescence detector array to detect fluorescing
reaction preferentially on an incoming proton beam side of a target
object or at various locations with a reference of 4.pi. to the
object, a gamma-insensitive neutron detector array to detect
neutrons emitted in a photofission reaction with material included
in a target object, a high-Z sandwich detector array, a
non-resonant detector array, a resonant detector array enriched
with a sample of an element that is being detected. These may be
provided singly or in combination to enable a variety of contraband
detection modalities. Further contemplated is the addition of
detector means including means selected from the group comprising:
X-ray/CT-X-ray detection, Dual energy X-ray detection, multiple
energy/multiple beam CT-X-ray X-ray Backscatter, X-Ray Diffraction
and Terahertz interrogation devices. Further contemplated is the
addition of passive detector means including a vapor detection
device, and/or a radiation detection device, and or Terahertz
Camera, Quadrapole Resonance devices.
[0013] Enabling multi-modal detection of the contraband detection
system is the provision of gamma beam generating proton beam
targets in a variety of configurations that include, but are not
limited to: a composite configuration comprising two or more
different materials for generating multiple gamma ray beams each
associated with a reaction of protons with a respective material; a
layered configuration comprising two or more different materials
for generating multiple gamma ray beams each associated with a
reaction of protons with a respective material; and, a segmented
configuration comprising at least two different materials for
generating multiple gamma ray beams each associated with a reaction
of protons with a respective material. An additional means of
producing the multiple beams includes the use of more than one
proton accelerator and target configuration each producing its own
selective gamma beam. Another means of producing multiple beams
includes a means of splitting or switching the primary proton beam
into different beam transports each specifically designed to adjust
the beam energy and parameters prior to impinging on individual
targets.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Further features, aspects and advantages of the apparatus
and methods of the present invention will become better understood
with regard to the following description, appended claims, and the
accompanying drawings where:
[0015] FIG. 1(a) illustrates a contraband detection system (CDS)
according to one aspect of the invention;
[0016] FIG. 1(b) depicts the exemplary gamma beam geometry in the
CDS depicted in FIG. 1(a);
[0017] FIG. 2 is a conceptual 3-dimensional view encapsulating an
exemplary CDS process including gamma-beam production, collimation,
and detection wherein the gamma-rays produced appear as an open
umbrella with the proton beam acting as an axis;
[0018] FIG. 3 depicts the system of FIG. 2 utilized for scanning an
example air cargo container using gamma-resonance detectors of a
modality adapted to map of the total density and the nitrogen
density of the container contents thus indicating resonance
detection of nitrogen;
[0019] FIGS. 4(a) and 4(b) illustrate example results obtained when
the system of FIG. 3 is utilized in a modality for detecting
delayed neutron detection due to photofission with FIG. 4(a)
illustrating delayed neutrons from a cargo container with nuclear
material inside and delayed neutrons from a cargo container without
nuclear material inside (FIG. 4(b));
[0020] FIG. 5 depicts a CDS system utilizing two proton
accelerators adapted for inspecting multiple target objects in a
single line system;
[0021] FIG. 6 depicts a single system including a proton beam
accelerator and proton beam target for producing gamma beams that
simultaneously feed four (4) inspection stations;
[0022] FIG. 7 depicts a single system including a single source
supporting two conveyors for detecting contraband in small parcels
or baggage.
[0023] FIG. 8 depicts a single system including a large detector
array for inspecting large containers;
[0024] FIG. 9 depicts a single proton beam accelerator feeding
multiple inspection nodes with each node capable of inspecting four
inspection stations in accordance with the embodiment depicted in
Figure as in FIG. 6;
[0025] FIG. 10 depicts a transportable CDS system, e.g., a single
system, wholly contained in a vehicle, such as a truck, for
instance, and shown inspecting a target container such as an LD3
container;
[0026] FIG. 11 depicts a CDS system including detectors for
measuring Gamma Resonance Absorption combined with detectors for
measuring Gamma Resonance Fluorescence; and,
[0027] FIG. 12 depicts an example of standoff CDS system including
a vehicle mounted unit provided for inspecting another vehicle from
a distance.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0028] The present invention is further directed to CD systems that
incorporate the production of mono-energetic gamma beams produced
by (a) beam production system(s) which include(s) a means for
producing accelerated protons or heavier ions to specific energies
to impinge upon and interact with (a) target(s) devices that
produce (a) specifically tuned mono-energetic gamma ray beam(s) for
active probe non-invasive interrogation. Preferably, the described
CD systems may incorporate one or more accelerator units to provide
the required proton beams to impinge upon one or more targets each
producing one or more mono-energetic gamma beams for active
interrogation. The gamma beams are chosen in the one case to
provide specific resonant interaction with the nucleus of specific
elements of interest common to the contraband of interest and, in
the other case, to produce additional non-resonant gamma beams for
imaging and interrogation. The system is unique in that Nuclear
Resonance Fluorescence and/or Nuclear Resonance Absorption and/or
non-resonant absorption and/or Photo-fission phenomena are utilized
simultaneously by the same active beams(s). The non-resonant
absorption/attenuation of the beam(s) is used for imaging the total
density similar to normal x-ray, dual energy x-ray and cat-scan
(3-D tomography). Tomography may be accomplished by rotation of the
object, rotation of the beams, or multiple beams at various angles.
Similarly the combination of elemental resonant absorption and/or
attenuation of the beam(s) may be measured simultaneously by the
same means utilizing different detector arrays.
[0029] It should be understood that a combination of two or more
resonant and/or non-resonant beams may be generated that are
separated by several MeV and the measured absorption/attenuation of
each in comparison with the other allows for an algorithm to
provide a sensitive measure of the "Z" (atomic number) of the
materials within the scanned object rapidly. This is similar to
methods used in DEXA Dual Energy X-Ray Analysis for X-ray measure
of body composition e.g., calcium densities. This provides for
detection of high-Z materials in nuclear threats and shielding used
in concealing these threats. According to the invention, gamma
absorption and/or fluorescence measurements are detected by single
and/or arrays of commercially available gamma detectors and/or
energy discriminating detectors and/or position sensitive detectors
and/or resonant detectors, and/or composite sandwich resonant
detectors (detecting multiple resonant signals from multiple
elements and, simultaneously, non-resonant signals in the same
detector), etc. Ratios of elemental to total density and element to
element density and/or threat algorithms using these in combination
with image recognition and cross correlation with additional
information provided by the interrogating beams and detector
combinations will provide for automatic detection of specific
threat objects, and provide indication of type and quantity. The
image produced will provide further information for evaluation of
the threat shape, size and location. The resonant fluorescence
measurements are used simultaneously to provide detection and
imaging of specific elements of interest. It does not require
resonant detectors however, these may be used for separation of
resonant and non-resonant gamma rays. Imaging can be accomplished
by several means including PET or like scanners or reverse
reconstructive imaging. This may be also used independently as
standoff detection or single sided detection as would be required
in some instances such as landmines, buried UXO (unexploded
ordinance) or other applications where the scanned object does not
allow for detectors on the far side such as standoff detection for
trucks and vehicles. The use of mono-energetic gamma beams provides
for an additional identification of nuclear materials and threats
with the selection of at least one of the beams at energy above the
threshold for inducing Photo-fission (approximately 6 MeV) within
the nuclear material. In this case specific neutrons will be
emitted indicating the presence of specific nuclear materials even
in the case of shielded materials. The measure of these neutrons
requires (a) specific neutron detector(s). Gamma insensitive
detectors such as (a) .sup.3He--Xe neutron detector(s) may be
employed for this purpose.
[0030] The proton beam targets used for gamma beam production are
chosen by required proton or heavier ion beam energy and target
element, for instance, as described in U.S. Pat. No. 5,040,200,
U.S. Pat. No. 5,323,004 and U.S. Pat. No. 5,293,414 the whole
contents and disclosure of each are incorporated by reference as if
fully set forth herein. Each of the patents includes also an
overall description of the process and specifies requirements for
detectors and the types of resonant detectors. Specifications for a
high current proton beam target are provided in U.S. Pat. No.
6,215,851 incorporated by reference herein, and include a .sup.13C
diamond layer proton beam target designs utilized in the
electrostatic accelerator and RF accelerator based CDS systems as
described in co-pending U.S. Provisional Application No. 60/492,749
the whole contents and disclosure of each are incorporated by
reference as if fully set forth herein herein.
[0031] Additional proton beam targets may be constructed as
composite, segmented and/or layered materials such as a Boron
Carbide (B.sub.4C) target enriched with .sup.13C to producing
multiple beams of 4.4 MeV, and 12 MeV gamma ray beams from Boron
and 9.17 MeV from the .sup.13C through (p,.gamma.) resonance
reactions. Other composite targets may be designed in similar
fashion to produce multiple beams, e.g., .sup.26Mg and .sup.30Si at
about 1.94 MeV and about 1.91 MeV, respectively, to detect .sup.14N
with .gamma. 9.173 MeV, .sup.16O with .gamma. 9.082 MeV and
.sup.35Cl with .gamma. 7.117 MeV. Other targets such as .sup.19F
may be used for the .sup.19F (p,.alpha..gamma.) .sup.16O reaction
for .sup.16O and to induce neutron emission from fissile and
fissionable materials as well as certain non-fissional controlled
materials. The proton beam target designs may also be segmented and
rotating.
[0032] Configurations of CDS systems according to the invention are
flexible and cost effective in that the proton beam targets may be
further constructed either of single elements, composite elements,
layered elements or segmented elements to provide one or more
multiple mono-energetic beams each independent in energy for
simultaneous scanning for one or multiple elements and providing
the capability for inducing Photo-fission and sensitive efficient
measure of high-Z elements. The gamma ray beam geometry allows for
scanning of multiple objects at the same time from each target and
detector set. The system geometry allows for each single
accelerator to support multiple detection stations simultaneously
and/or beam splitting and/or beam switching and/or timesharing each
with the capacity to scan multiple objects at the same time. Both
the beam geometry and system geometry provides the capability to
scan inline (conveyor or other) a flow of objects while moving
alarmed objects (possible threats) to another portion of the same
beam for continuous in depth examination. This allows for high
throughput with resolution of alarms simultaneously. The entire
system may be operated remotely by an operator at a separate
location than the system, or objects may be scanned at a distance
(e.g., standoff detection as shown in FIG. 15) where the entire
system is remote from the object being interrogated.
[0033] It is understood that other targets may be constructed
including composite and/or layered materials capable of producing
specifically tuned gamma beams signal or multiple gamma ray beams
at different energies, for detection/identification of evolving
threat materials. Furthermore, other targets may be implemented to
enhance gamma beam(s) quality and system performance (e.g., provide
a target with increased ability to withstand high heat of
accelerating protons).
[0034] The key advantage of the system is its concurrent use of
three inspection modalities that significantly augment the
detectability of nuclear threat materials. These modalities
include: 1) Photofission--In fissile materials, gamma rays with
energies above about 5.6 MeV undergo a photofission reaction
inducing emission of prompt- and delayed-neutrons that are detected
using neutron detectors. Detection of delayed neutrons is an
unequivocal signature of the presence of nuclear materials with
some possibility for identifying them; 2) High Z--Dual- or
triple-energy beam absorptiometry separates materials with
different electron densities. In addition to Compton scattering,
gamma rays at energies above about 5 MeV interact by pair
production providing increased sensitivity to high-Z materials.
Thus, by monitoring the intensity ratios of the gamma-ray beams,
high and low Z materials can be discriminated, in contrast to other
ways in which they may represent the same optical thickness to a
single energy beam. It is understood that a .sup.13C target, with
the addition of one or more isotopes, will support differentiation
of high-Z materials; and, 3) Resonance--When finely tuned to the
first nuclear level of an element of interest, gamma rays will
undergo element-specific resonance attenuation and fluorescence, in
addition to the photoelectric-, Compton-, and pair-production
processes. For example, gamma rays at about 9.17 MeV will interact
specifically with nitrogen encountered in all high explosives.
Additional specifically tuned gamma beams will identify elements
required to identify evolving threat materials.
[0035] The CDS systems described herein employing use of the new
proton beam targets may be used in a variety of modalities.
However, one such CDS mode described herein with respect to FIG. 2,
encapsulates the entire process 100 for gamma-beam production,
collimation, and detection and employs the use of the enriched
boron-carbide (B.sub.4C) proton beam target. As shown in FIG. 2, an
intense proton beam 110, e.g., at an energy of about 1.75 MeV
generated from an accelerator 105 such as described herein,
impinges upon the boron-carbide (B.sub.4C) target 112 enriched with
.sup.13C to produce two gamma-ray beams 115 from Boron, at respect
energies of 4.4 MeV, and 12 MeV, and a single gamma-ray beam 116 of
an energy of about 9.17 MeV from the .sup.13C through (p,.gamma.)
resonance reactions. From a small spot on the target these gamma
rays are emitted in all directions with small variations in their
intensities, due to the angular correlation, and in their energy
due to Doppler shift resulting from proton absorption by the
nuclei. Using shielding materials surrounding the target, the gamma
rays are collimated to a conical envelope with an opening angle of
about 80.7.degree. relative to the proton beam's axis and an
angular width of 0.7.degree.. Thus, a gamma ray beam fan 120 is
created that appears as an open umbrella with the proton beam 110
acting as an axis as shown in the conceptual 3-dimensional view of
the system shown in FIG. 2.
[0036] It is understood that this technique described herein with
respect to FIG. 2 may be extended to provide gammas at other
specific energies that are resonant with other elements such as
carbon, oxygen, and chlorine. By combining the specific absorption
of the various gammas, the ratios of the elemental composition of
the intervening material can be deduced, giving a very specific
detection of the material. Measurement of the total and nitrogen
densities enable the detection of explosives and combining a
measurement of carbon or oxygen will improve the technique even
further. Also, measurement of chlorine will make it possible to
detect other explosives. To make these multiple-energy gamma beams
requires a target that has one or more additional isotopes applied
along with the .sup.13C during target fabrication.
[0037] The specific angles are required to satisfy resonance
conditions of the 9.17 MeV gamma-ray beam interacting with
nitrogen. No such requirements exist for photofission or beam
absorptiometry. As shown in FIG. 2, once the gamma beam fan 120
intercepts a targeted object 122, for example, a parcel or a cargo
container, and interacts with its content, it is subsequently
monitored by an array of detectors 125 encompassing the object.
These include a linear array of resonance detectors, especially
developed and tested for nitrogen detection that would, by
scanning, display a 2-D distribution, or, by utilizing a rotating
mechanism, a 3-D distribution of nitrogen (explosives) in the
object. The same array may consist of BGO or Sodium Iodide, High-Z
sandwich, or other detectors. At the same time, the system also
displays a map of the total density of the object. Additional
conventional detector arrays (not shown) may assist in detecting
and imaging non-resonant radiation, and detector arrays on the near
side of the object can detect gamma resonance fluorescence, while a
separate battery of neutron detectors may be provided that are
responsible for detecting neutrons induced by photofission.
[0038] Two of the proposed modalities are demonstrated for an
exemplary CDS 150 shown in FIG. 3, which depicts the system of FIG.
2 utilized for scanning an example LD-3 (International Air
Transport Association specified) air cargo container 152 using
gamma-resonance detectors 155. As shown in FIGS. 3(a) and 3(b), the
two demonstrated modalities results in two images: for example, a
first image 160 representing the map of the total density of the
container contents and, a second image 170 representing the map of
the nitrogen density of the container contents indicating resonance
detection of nitrogen. The basic results for a delayed neutron
detection due to a photofission reaction are additionally shown in
FIGS. 4(a) and 4(b), respectively, that depict a neutron
measurement following a pulse of high-energy gammas as a function
of time. FIG. 4(a) particularly depicts an example delayed neutron
measurement plot 180 illustrating a large number of delayed
neutrons emitted from a cargo container after only 2 ms indicating
presence of nuclear material inside and, a delayed neutron
measurement plot 182 indicating delayed neutrons emitted from a
cargo container without nuclear material inside (FIG. 4(b)).
[0039] FIG. 5 depicts a multimode CDS system 200 including an
expansion of the basic CDS unit (of FIG. 2) by adding various
detection systems and accelerators to a single high voltage
generator 202. More particularly, FIG. 5 depicts a conceptual
example of a single line CDS system 200 utilizing two proton
accelerators 205a and 205b (a "two head" system) adapted for
inspecting a plurality of target objects, for example, four cargo
containers. As shown in the FIG. 5, each of four containers 222a, .
. . , 222d may be simultaneously inspected. At each container being
inspected, a variety of detector arrays are shown including: a NFD
(nuclear resonance fluorescence detector) array(s) 225 shown on the
inner side of containers 222a and 222b before the high energy
proton beam split (i.e., incoming beam side) so as to avoid picking
up absorption or gamma rays going in, but what is fluorescing
coming out (all directions); a ND (Neutron detector) array(s) 226
shown on the outside of the containers, and are actually gamma
insensitive neutron detectors to detect neutrons emitted in the
photofission; a NRD (non-resonant detector) array(s) 227
comprising, for example, BGO, sodium iodide, etc.; and, a RD
(resonant detector) array(s) 228 that includes a sample of the
element that is being detected (e.g., will fluroresce when element
detected). The configuration depicted in FIG. 5 is a basic
configuration comprising the following elements: a single high
voltage power supply or generator 202, two proton beam accelerators
205a and 205b (however, it is understood that only one accelerator
may be implemented), one or multiple targets 222a, . . . , 222d,
and, the combinations of the NFD, ND, NRD and RD detectors in
arrays.
[0040] A portal array for passive detectors can be easily
integrated within the CDS system(s) depicted in FIGS. 2 and 5. In
such CDS system(s), additional active means of detection including
X-ray/CT-X-ray, Dual energy X-ray, Multiple energy/multiple beam
CT-X-ray and/or X-ray Diffraction are incorporated for enhanced
imaging and measure of Z and density. Nuclear Quadrapole Resonance
(NQR) detection may additionally be incorporated into the overall
system to provide specific molecular detection. Nuclear Magnetic
Resonance (NMR) detection combined with Electron Spin Resonance
(ESR) (overhauser effect) such as described in U.S. Pat. No.
4,719,425, the whole contents and disclosure of which is
incorporated by reference herein, may also be incorporated for
additional molecular identification. Multi-resonant broadband
spectroscopy and imaging may also be incorporated into the system.
The incorporation of Terahertz interrogation or Terahertz Camera
may also be included. Additional passive detectors may also be
incorporated for sensing by vapor detection, and additional nuclear
detection may be incorporated with passive sensitive neutron and
gamma detectors both imaging and non-imaging.
[0041] FIG. 6 depicts a single CDS system 250 including a proton
beam accelerator 255 and proton beam target 252 for gamma beam
production that feeds simultaneously four (4) inspection nodes or
stations. In this single system embodiment, the gamma beams 265a, .
. . ,265d emanate in a circle (e.g., in a cone) from the target
252, and may be used to inspect four (4) target objects (e.g., LD3
containers) simultaneously. It is understood that additional
objects may be detected in this configuration.
[0042] FIG. 7 depicts a single CDS system 300 including a single
source supporting two conveyors 305a, b for detecting contraband in
small parcels or baggage that have been conveyed and/or diverted
into each of two detection stations. For example, an accelerator
(not shown) is located under the floor below a baggage conveyor
system 305, and the target (not shown) may be in a central
location. It is understood that multiple (e.g., four) objects on
conveyors may be simultaneously inspected (as in FIG. 6), although
only two conveyors are shown at either side of the target for
checking checked-in or carry-on baggage. It is understood that
while the gamma beams may be sourced from underneath the floor, the
accelerator may be remote from the scanning stations. For example,
in one embodiment, the proton beam may be bent up onto a .sup.13C
proton beam target, causing gammas to emanate in a horizontal
plane. In the system 300 shown in FIG. 10, the gamma beam is
collimated into two .about.20.degree. sections 310a, 310b, which
scan bags on the respective conveyors 305a, 305b. Such a system,
using a 10 mA accelerator, may inspect up to 1600 bags/hour for
nitrogen-bearing explosives. In another embodiment, the accelerator
again may be located below the baggage-handling level, but its beam
would be horizontal and the gamma fan nearly vertical. Detectors
mounted above the conveyors could scan in a vertical section
through the bags. These configurations would depend on the
available space and layout of the facility. In either of them, the
scan time for a luggage-size parcel is less than 6 sec.
[0043] FIG. 8 depicts a single system 400 including a large
detector array 425 for inspecting large containers. The system 400
of FIG. 8 is an RF accelerator based system including an RF power
source 402, an RF proton beam accelerator 410 and a gamma
production target 412 such as described herein. A container handler
418, e.g., conveyor, is provided that is subject to a produced
resonant gamma ray fan 420. An array of resonant type detectors 425
such as described herein are provided that detect nuclear
resonance-type phenomena.
[0044] FIG. 9 depicts a single CDS system 500 utilizing a single
proton beam accelerator 502 feeding multiple inspection nodes with
each node capable of inspecting four inspection stations in
accordance with the embodiment as depicted in FIG. 6. In the system
500 depicted in FIG. 9, the accelerator is remotely located (e.g.,
outside an airport terminal or on the roof of a building), and the
proton beam lines 510a-510c (similar to waveguides) are run to
different locations in the building which hit a target for raster
scanning multiple nodes 503a-503c off the accelerator. Although at
each node only a single arc (gamma beams) is depicted, each node
may handle two or four conveyors (objects). Thus, FIG. 9 depicts a
beam-splitting or time sharing configuration utilizing beam
switching mechanisms 506.
[0045] FIG. 10 depicts a transportable CDS system 600, e.g., a
single system, wholly contained in a vehicle 650, such as a truck,
for instance, and shown inspecting a target container such as an
LD3 container.
[0046] FIG. 11 depicts a basic Gamma Resonance Absorption system
700 combined with a Gamma Resonance Fluorescence mode. In this
embodiment, there is a proton beam accelerator 702 producing a
proton beam that hits a target that gives off gamma rays that pass
through the target object (e.g., a container) with an array of
primary detectors 725a provided for measuring gamma resonance
absorption, and an array of secondary detectors 725b provided for
measuring gamma ray fluorescing. It is understood that the location
of the secondary detectors 725b may be placed anywhere, and,
skilled artisans will note that based on fluorescence properties of
particular contraband elements, objects may be located at specific
angles with respect to the incoming gamma beam 720.
[0047] FIG. 12 depicts an example of standoff CDS system 800
including a vehicle 850 (e.g., truck) mounted unit provided for
inspecting another vehicle 875 (e.g., truck) from a distance (i.e.,
the whole system and operator are away from the scanned object). In
this example, the truck includes an arc of detectors 825 to provide
backscatter or fluorescence detection (e.g., nitrogen), and thus
can perform a single-sided scan. It is contemplated that the
distance between the mobile single system unit and the inspected
object (e.g., a truck) may be 100 yards, but depends upon the
ability to separate out gammas coming back (e.g., backscatter) from
gamma rays in the air. In this embodiment, the beam is located a
distance away, e.g., from a checkpoint, and is directed at the
truck to look for the contraband item (e.g., nitrogen) which
fluorescence or backscatter may be detected. If contraband is
detected, the truck may be further directed to a portal for further
imaging etc. Additionally shown are transportable and multiple
accelerator configurations including: a single power supply 900 and
single accelerator 902 producing a single fan beam 920 (see FIGS.
12(i) and 12(ii)); a single power supply and two accelerators 903
shown in a configuration with an accelerator on the side and on top
of the object for two simultaneous projections (see FIG. 12(iii));
and, a single power supply and three accelerators 904 shown in a
planar configuration (see FIG. 12(iv). It is understood that each
accelerator may have multiple-layered targets, segmented targets or
single targets for multi-mode detection, as described herein.
[0048] The CDS systems according to this aspect of the present
invention are unique due to the following factors: 1) they provide
for the simultaneous detection of a variety of materials such as
SNM, IND, explosives, and is expandable to detect additional threat
materials; 2) shielding in one modality is compensated by its
ineffectiveness in the other, e.g., water will shield neutron
emissions induced by photofission, but it can easily be
counterbalanced by concurrent high Z detection; 3) they are adapted
for generating either planar, 2D, or CT, 3D images that depend only
on the system architectures; 4) the systems may be automated using
threat algorithms due to the systems' high specificity; 5) they
achieve increased throughput due to multimodality in a single scan;
6) they may implement use of a single power supply that feed
several acceleration heads allowing for a distributed system at
considerably reduced cost; 7) the generate a gamma ray fan beam,
with each head feeding into several inspection stations; 8) the
systems' open architecture permits the same system to be used for
inspecting a variety of target objects including, but not limited
to: parcels, large cargo, cars, and boats; 9) the same systems have
secondary uses for unrelated military and medical applications.
[0049] While the invention has been particularly shown and
described with respect to illustrative and preformed embodiments
thereof, it will be understood by those skilled in the art that the
foregoing and other changes in form and details may be made therein
without departing from the spirit and scope of the invention which
should be limited only by the scope of the appended claims.
* * * * *